Curie point valve



June 24,1952 R A WITTMANN 2,601,579

CURIE POINT VALVE Filed May 22, 1948 I l f6 j. /6 )50 f5, 2.5' @1 \L\ mPatented June 24, 1952 UNITED STATES PATENT OFFI CURIE POINT VALVERobert A. Wittmann, Chicago, Ill.

Application May 22, 1948, Serial No. 28,640

6 Claims. 1

My invention relates, generally, to valves and it has particularrelation to valves that are controlled in response to predeterminedtemperature change.

Among the objects of my invention are: To employ a stationarily mountedmagnet, such as a permanent magnet, and Curie point metal forcontrolling the movement of a valve member to open or close a valvedepending upon whether the metal is abovev or below its Curie point; tobias the valve member to close one of the valve ports; to employ gravityas the biasing force; to position the Curie point metal underneath thepermanent magnet `where it shunts the flux thereof when it is below theCurie point and permits the magnet to attract the valve member when itis above the Curie point; to position the permanent magnet, Curie pointmetal and valve member in a housing of non-magnetic material having ahigh thermal conductivity; to locate one port in the upper part of thehousing and another port in the lower part of the housing with acommunication therebetween through the permanent magnet and Curie pointmetal; to employ a spherical member of magnetic material for the valvemember; to employ this construction in a three way valve; and to jointhe upper and lower portions of the housing together by an annulus ofCurie point metal.

Other objects of my invention will, in part, be obvious and in partappear hereinafter.

My invention is disclosed in the embodiments thereof shown in theaccompanying drawing and it comprises the combination of elements andarrangement of parts which will be exemplified in the constructionshereinafter set forth and the scope of the application of which will beindicated in the appended claims.

For a more complete understanding of the nature'and scope of myinvention reference can be had to the following detailed description,taken together with the accompanying drawing, in which:

Figure 1 is a view partly in elevation and partly in section taken alongthe line I-I of Figure 2 and showing one embodiment of my invention;

Figure 2 is a view, in side elevation, of a valve in which my inventionis embodied;

Figure 3 is a view, similar to Figure 1, but showing the valve in theopen position;

Figure 4 shows a three way valve embodying the present invention, thevalve member being shown in the unattracted position;

Figure 5 is a view, similar to Figure 4, but

2 showing the valve member in the attracted position; and v Figure 6 isa vertical cross-sectional view of a further modification of myinvention in which a portion of the valve housing is formed by anannulus of Curie point metal which is also employed for shunting theflux of the permanent magnet under certain operating conditions.

Referring now particularly to Figures 1, 2 and 3 of the drawing. it willbe observed that the reference character I0 designates, generally, avalve of the two way type which may be employed in the ignition systemsdisclosed in my copending applications Serial Nos. 722,584 and 767,707,filed, respectively, January 17, 1947, and August 9, 1947. Otherapplications of the valve I0 will be apparent to those skilled in theart, reference being had to these copending applications forillustrative. purposes only.

The valve I0 includes a valve housing which is indicated, generally, atII and is formed of non-magnetic material such as brass, stainlesssteel, etc. In some applications the valve housing may be formed ofCurie point metal. The valve housing II is circular in cross-section andhas an upper valve housing portion I2 which is larger in diameter than alower valve housing portion I3, these portions being interconnected byan intermediate portion I4 which provides a step or shoulder thefunction of which will be apparent presently. The upper end of the valvehousing Il may be closed by a cover I5 which may be secured in place bysuitable screws I6. At the lower end of the lower valve housing portionI3 a cover II may be secured by suitable means.

A port I8 is provided in the lower cover I'I and, for illustrativepurposes, the port I8 can be considered an exhaust or outlet port. Theport I8 has a conical valve seat I9 which is arranged to be engaged by avalve member 20 in the form of a sphere normally of magnetic material.For a purpose to be explained hereinafter the valve member 20 may beformed of Curie point metal. When the valve member 20 engages thespherical valve seat I9. the exhaust port I8 is closed or sealed againstthe flow therethrough of iluid, such as gas, which may be used forheating or cooking purposes or for creating pressure on a diaphragm, orfor other purposes. A valve port 2| may be provided in the upper valvehousing portion I2. Since the valve port I8 is considered to be anexhaust port, theV valve port 2| can be considered to be an inlet orintake port. However. it will be understood that the functions of theports I8 and 2| can be reversed.

Immediately above the valve member 2U and resting on the shoulder whichis provided by the intermediate portion I4 of the valve housing II is abody 24 of Curie point metal which is annular in shape and serves tosupport a stationary magnet which may be a permanent magnet or anelectromagnet. Magnet 25 of Figures 1, 2 and 3 is a permanent magnet ofan inverted U- shape having pole extensions 2S and 21 which constitutethe magnet arms. The space 28 between the pole extensions 26 and 21serves to` provide part of the communicating passageway between theintake port 2| and the exhaust port I8. In the body 24 of Curie pointmetal there is a central opening 29 which has an out-flared portion 30which is directed toward the valve member 20. A pin 3l of non-magneticmaterial such as brass or stainless steel extends through the permanentmagnet 25 and into the opening 25 and serves to limit the upwardmovement of the valve member 20 when it is attracted by the permanentmagnet 25 under certain operating conditions to be described presently.When the valve member 201 is in the attracted position as shown inFigure 3 the inlet port 2l is placed in communication with the exhaustport I8 through the transverse passageway 28 in the permanent magnet 25and the opening 29 in the body 24 of Curie point metal. In the attractedposition the valve member 20 is moved away from the valve seat I9 toopen the normally closed exhaust` port I8.

It is Well known that Curie point metal has the property of changingfrom a magnetic to a non-magnetic material depending upon its temperturewith respect to its Curie point. When the body 24 of Curie point metalis heated to a temperature above its Curie point, it is nonmagnetic.When the body of Curie point metal is at a temperature below its Curiepoint, it has magnetic properties and, since it is positioned above thevalve member 20 and below the permanent magnet 25,- it shunts themagnetic flux `of the latter and prevents the valve member 20 from beingattracted upwardly against the normal biasing force of gravity whichurges the valve member 2U into sealing engagement with the valve seat I9to close the exhaust port I8. However, when the body 24 of Curie pointmetal is heated above its Curie point, it loses its magneticcharacteristics Aor permeability and the flux of the magnet 25 no longeris shunted thereby. The design of the parts making up the valve IIl issuch that under these conditions, the permanent magnet 25 is capable ofattracting the valve member 20 and overcoming the biasing force ofgravity urging the same downwardly. Accordingly, when the valve member20 is attracted by the permanent magnet 25 to the position shown inFigure 3, the valve I is opened. v

By way of illustration` it is pointed out that the valve III may beemployed in conjunction with a pilot jet. 32 of a gas burning devicesuch as a kitchen range, gas furnace or the like. The flame 33 from thepilot jet 32 impinges on the valve housing II which, as indicated, isformed of a material having a relatively high heat conductivity. Theheat from lthe flame 33 is transmitted to the body 24 of Curie pointmetal land it `is suil'cient to heat the same above its Curie pol-nt andmaintain it -in this operating condition. Therefore, as long as theflame 33 continues to impinge against the Valve housing II,

the body 24 is maintained above its Curie point and the permanent magnet25 holds the valve member 20 in the attracted position shown in Figure3, thereby maintaining the valve I0 in the open position.

When the flame 33 is extinguished, as illustrated in Figure 1, the body24 cools below its Curie point, becomes magnetic and shunts the fluxfrom the permanent magnet 25. The biasing force of gravity then issuicient to overcome what residual magnetic attraction there may be forholding th-e valve member 2U in the upper position and, as a result, thevalve member 20 dro-ps to the position shown in Figure 1, therebyclosing the valve I.

Immediately after the flame 33 is extinguished the Curie point bodymember 24 will still be above its Curie point so that the valve 28 willremain in its attracted position, as shown in Figure 3. Consequently,gas will continue to flow through the valve I0 and the flow of gas willserve to hasten the cooling of the Curie point body 24 since it isdirectly in the path of the flowing gas. As a result. the temperature ofthe body 24 will quickly drop below its Curie point and the valve willpromptly close by reason of the body 24 regaining its permeability andshunting the flux of magnet 25, whereupon the valve member 20 drops onto its valve seat I9.

While a flame 33 has been illustrated as being employed for changing thetemperature of the body 24 of Curie point metal, it will be understoodthat other sources of heat, such as electrical heating devices, may beemployed for controlling the functioning of the valve I0. Accordingly,lit will be understood that the flame 33 is shown for illustrativepurposes only and is not to be co'nsidered as being the only source ofheat that can be employed for controlling the functioning of the valveI0.

For the purpose of providing a safety featur in the Valve I0 it iscontemplated that the valve member 2D itself be constructed of Curiepoint metal, but having a higher Curie point than the body member 24. Inthe event that the valve should become overheated due to a defect inassociated appliances, the valve member 20 would eventually becomeheated above its Curie point, and drop away from the magnet 25 'and onto its seat I9, whereby the valve would be closed. However, in normaloperation, the temperature of the valve member 28 would be well belowits Curie point.

The valve IIJ shown in Figures 1, 2 and 3 land described hereinbefore isof the two way type, i. e. it has two ports I8 vand 2I. If desiredanother port can be provided thus making it a three way Valve.

In Figures 4 and 5 of the drawing there is' i1- lustrated a valve I0'which is of the three way type. That is, 'in addition to having thevalve ports I8 `and 2I, previously described, it also may have a thirdport 36. The valve member 20 is arranged as before to control theopeningor closing of the port I8. When the valve member l2'I'l occupies theposition shown in Figure 4 of the drawing, the ports 2I and 36 areplaced in communication through an out-flared opening 30 in the body 24of Curie point metal and a transverse passageway 28 between the poleextensions 2E Vand 2'I of the permanent magnet 25'. Now, when the ame 33heats thebody 24 above its vCurie point, the valve and the 'v alvemember 20 is moved upwardly to `close off the out-flared passagewayV'38' in the body 24", as il- -lustrated in Figure 5, thereby cutting oicommunication with the valve port 2| and placing the valve ports I8 and36 in communication. It will be observed that the valve housing |I forthe valve I shown in Figures 4 and 5 of the I drawing is essentially thesameas the valvehous- .housing I I and serves to interconnect the' upperand lower valve housing portions |I2 and 3. The valve I |0 shown inFigure 6 is of the two way type, communication between the parts IIB andI2| being provided through a transverse passageway |28 in the permanentmagnet |25. A pin "|3I of non-magnetic material such as brass -orstainless steel extends centrally through the permanent magnet |25 andit has a head |39 at its lower end the under surface |40 of which headis concave for receiving the valve member |20 when it is attractedupwardly by the permanent magnet |25 when the body |24 of Curie pointmetal is heated above its Curie point in the manner describedhereinbefore.

It will be observed that the lower portion II3 of the valve housing isof a smaller diameter than that shown in the valve housings I and Il ofFigures 1 and 4, respectively. The lower portion ||3 thereby serves as aguide for the vertically moving valve member |20, while yet providingclearance between itself and said valve member for uid flow. By havingthe valve seat |I9 conical and downwardly inclined and of suflicientradial extent, it will be seen that even when the valve member |20descends along the inner side wall of lower portion II3 of valve housingit will be directed to a central position on the valve seat ||9 to closethe port I|8. It will readily be observed that if the conical valve seatextends radially to a position wherein its periphery is at a distancefrom the inner side wall of lower portion II3 of valve housing less thanthe radius of the valve member |20, then the valve member will always bedirected to a central position on the valve seat |I9. As an alternative,the bottom wall |I1 of housing may be downwardly inclined toward port I8over the whole inner surface of said wall.

Since certain further changes can be made in the foregoing constructionsand different embodiments of the invention can be made without departingfrom the spirit and scope thereof, it is intended that all matter shownin the accompanying drawing and described hereinbefore shall beinterpreted as illustrative and not in a limiting sense.

I claim as my invention:

1. In a valve, in combination, a valve housing of non-magnetic materialadapted to be located in an upright position and having intake andexhaust ports one of which is located in the bottom of said housing andthe other is located in the upper part thereof, a valve member ofmagnetic material gravity biased to close said one port, a permanentmagnet of inverted U-shape in said upper part of said housing forattracting said valve member to move the same upwardly and open thevalve by placing said ports in communication through the passagewaybetween the downwardly extending poles of said permanent magnet, and aring of Curie point metal underneath said permanent magnet for shuntingits flux when said metal is below its Curie point whereby said valvemember is not attracted and the valve lremains closed, the opening in.said ring `registering with said passageway. f

2. In a valve, in combination, a valve housing of non-magnetic materialadapted to be located in an upright position and havingl intake andexhaust ports one of which is located in'the'bottom of said housing andthe. other of which is located inthe upper part thereof, a freelymovable spherical valve member of magnetic material gravity biased toclose said one port, a permarient magnet of inverted U-shape in saidupper part of said housing for attracting said Valve member to move thesame upwardly and open the valve by placing said ports in communicationthrough the passageway between the downwardly extending poles of'saidpermanent magnet, non-magnetic stop means against which said valvemember is attracted by said permanent magnet and positioned so as not toprevent the now of fluid from the intake port to the exhaust port, and aring of Curie point metal underneath said permanent magnet for shuntingits flux when said metal is below its Curie point whereby said valvemember is not attracted and the valve remains closed, the opening insaid ring registering with said passageway.

3. In a valve, in combination, a valve housing, a wall of Curie pointmetal dividing the housing into upper and lower portions and dening apassageway and a valve seat between said portions, a rlrst port and asecond port located in the lower portion of the housing and a third portbeing located in the upper portion of the housing, a valve member ofmagnetic material for closing said first port, the second port and thirdport being in communication with said passageway when the valve membercloses the rst port, a magnet in the upper portion of the housing, saidwall of Curie point metal being adapted to shunt the magnetic flux ofsaid magnet when said metal is below its Curie point, thereby renderingthe magnet ineffective to actuate the valve member, and also beingadapted to be heated above its Curie point whereby it loses itspermeability and permits the magnet to attract the valve member to thevalve seat to close off the passageway in the dividing wall and therebyprovides communication between the first port and the second port, saiddividing wall being disposed in the path of iiuid flow and to thecooling effect thereof.

4. In a valve, in combination, a valve housing of non-magnetic materialadapted to be located in an upright position and having intake andexhaust ports one of which is located in the bottom of said housing, aspherical valve member of magnetic material gravity biased to close saidone port, a permanent magnet in an upper part of said housing forattracting said valve member to move the same upwardly and open thevalve, and a body of Curie point metal underneath said permanent magnetfor shunting its fluxi when said metal is below its Curie point wherebysaid valve member is not attracted and the valve remains closed, saidother port being located in the upper part of the housing andcommunicating with said one port through a passageway extending throughthe permanent magnet and the body of Curie point metal.

5. The invention, as set forth in claim 4, wherein a third port islocated in the lower part of the housing and the valve member in theattracted position closes the passageway to said other port and placessaid third port in communication with said one port. said thitdvportbeing in communication with said other port when said one port is closedby said valve member.

6. In a valve, in combination, a valve housing adapted to be located inanl upright position and having intake and exhaust ports one of which islocated in the lower part o! said housing, a valve member of magneticmaterial gravity biased to close said one port. amagnet in saidl upperpart o! said housing for' attracting said valve member to move the sameupwardly and open the valve and a` body of Curie point metal underneathsaid magnet for shunting its ux when said metal is below its Curiepoint, whereby said valve member is not attracted and the valve remains`closed. said body of Curie point metal being in theforxn of an annulusand constituting a, partv of the housing` and joining the upper andlower portions thereof.

ROBERT A. WIT'IMANN.

REFERENCES cuan The' following references are of record in the le ofthis' patent:V l

UNITED STATES PATENTS '110,167' France July 9, 1934

